Modified PiWriter and PiParser in order to serialize project relative paths (for refinements and memory scripts) when possible.
Project relative paths are path without project names, with only path through the folders of the project.
Project relative paths are serialized rather than workspace relative paths when the files they point is contained by the same project as the .pi in which they are serialized.
Removed warnings for cast from Object to generic types (collections, maps...) by adding @SuppressWarnings("unchecked") annotations.
Removed warnings from useless imports.
Format + removal of useless lines.
Refactored PiWriter, PiParser and implementation classes of ports and interfaces in order to share Strings used as identifiers in xml files and kind attributes.
All the identifiers are now contained as public static final Strings in the PiIdentifiers class.